1. Field of the Invention
The present invention relates generally to an input device for use in a computer system. More particularly, the present invention relates to a mouse having an optically-based scrolling feature.
2. Description of the Related Art
Most computer systems, as for example general purpose computers such as portable computers and desktop computers, receive input from a user via an input device such as a mouse. As is generally well known, the mouse allows a user to move an input pointer (e.g., cursor) and to make selections with respect to a graphical user interface (GUI) on a display screen. The mouse typically includes a trackball or optical sensor (located at the bottom side of the mouse) for translating the motion of the users hand into signals that the computer system can use. For example, by positioning the mouse on a desktop and moving it thereon, the user can move an input pointer or cursor in similar directions within the GUI. The mouse also conventionally includes one or more buttons, which are located on the top side of the mouse. These one or more buttons, when selected, can initiate a GUI action such as menu or object selections. The one or more buttons are typically provided by on or more button caps that move relative to the housing (e.g., through an opening in the housing).
Recently, a scroll wheel has been added to the mouse to give the user scrolling functionality. The scroll wheel saves time and steps, and allows a user to move through documents by physically rolling the wheel forward or backward-instead of clicking on the scroll bar displayed on the GUI. In the past, scrolling was implemented by selecting the scroll bar with the mouse, and moving the scroll bar on the GUI by moving the mouse up or down. A switch has also been incorporated into some mice for changing the mouse from a cursor control device to a scroll control device. In cursor control mode, mouse movements control cursor movements, and in scroll control mode, mouse movements control scroll movements. In most cases, the scroll wheel and switch require a separate mechanical component for actuating the scrolling feature. These devices also generally require the mechanical component to be mounted in the mouse with portions of it protruding out of the mouse housing to allow a user's finger access, i.e., the housing includes a cut out to allow the mechanical component to protrude therethrough.
Although mice designs such as those described above work well, there are continuing efforts to improve their form, feel and functionality. For example, it would be desirable to provide an improved scrolling feature for a mouse that is aesthetically pleasing to the user. As should be appreciated, the scroll wheel is not aesthetically pleasing since it protrudes above the mouse housing, i.e., breaks the surface of the mouse. Furthermore, the scroll wheel of the mouse can only be manipulated in one direction, and thus the use of the scroll wheel becomes counter intuitive when scrolling in a different direction in the GUI, as for example directions that are orthogonal thereto. In addition, it would be desirable to provide an improved scrolling feature for a mouse that allows the mouse to scroll directly without holding down or physically moving a wheel, button, switch or the like.